The reforms, passed in 2011 by Republican lawmakers, severely limit the bargaining power of public sector unions while forcing most state workers to pay more for benefits such as health insurance and pensions. They also made payment of union dues voluntary and forced unions to be recertified every year.

The laws sparked efforts to recall Wisconsin Governor Scott Walker and some Republican lawmakers who voted for them. Walker survived a recall election last year.

Federal Judge William Conley in Madison wrote in his ruling that the First Amendment grants public employees the right to free speech and association, but does not grant them collective bargaining rights.

The reforms, which do not apply to public safety workers, do not violate equal protection rights of workers because the government has the right to set wages and benefits for individual workers based on performance and skills, according to Conley.